This research initiative is directed towards discovering the molecular and cellular activities that direct embryonic cells toward the creation of a highly specialized olfactory system in insects. The model organisms that the investigators propose to use in this study are heliothine moths in the genus Heliothis and Heliocoverpa (family Noctuidae). Studies of insect olfactory development are limited in scope, with the exception of Drosophila and the sphinx moth Manduca sexta. Thus, from a developmental biology perspective, heliothine moths may be considered an underrepresented model system in the field. This application highlights the usefulness of heliothine moth antennal imaginal discs for investigating key questions relating to pattern formation, cell fate specification, and organogenesis. The information obtained from this research will have broad implications in the field of sensory biology. Three questions will be addressed by this research. Specific Aim 1 will be directed towards elucidating the molecular basis of early patterning and cell fate specification during Heliothis antennal formation. The investigators propose to clone Heliothis homologues of known regulators of antennal development and to use these identified sequences as probes for characterizing the developmental transitions of the presumptive olfactory epithelium into the adult antennal organ. The reagents generated from this research will then be used to investigate two additional issues. Specific Aim 2 focuses on uncovering the molecular and cellular mechanisms that create sexually dimorphic antennae between male and female moths. Specific Aim 3 is then directed towards understanding how developmental events (gene expression, cell lineage, cell death) influence the creation of functionally distinct olfactory neuronal populations among related species of moths. Overall, this application addresses important questions in the field of developmental neurobiology and will contribute to our knowledge of olfactory systems in animals. PBULIC HEALTH RELEVANCE: The proposed research will provide key insights into the biological mechanisms that control the formation of insect sensory organs, specifically the olfactory system. Given the evolutionary connections between insects and vertebrates, this research will contribute to our broader understanding of the ways that embryos create complex sensory organs required for adult organisms to interact within their environment.